Spatiotemporal dissociation of brain activity underlying threat and reward in social anxiety disorder

Vulnerabilities in social anxiety: Integrating intra- and interpersonal perspectives

What are the major vulnerabilities in people with social anxiety? What are the most promising directions for translational research pertaining to this condition? The present paper provides an integrative summary of basic and applied translational research on social anxiety, emphasizing vulnerability factors. It is divided into two subsections: intrapersonal and interpersonal. The intrapersonal section synthesizes research relating to (a) self-representations and self-referential processes; (b) emotions and their regulation; and (c) cognitive biases: attention, interpretation and judgment, and memory. The interpersonal section summarizes findings regarding the systems of (a) approach and avoidance, (b) affiliation and social rank, and their implications for interpersonal impairments. Our review suggests that the science of social anxiety and, more generally, psychopathology may be advanced by examining processes and their underlying content within broad psychological systems. Increased interaction between basic and applied researchers to diversify and elaborate different perspectives on social anxiety is necessary for progress.

Amplification of Positivity Treatment for Anxiety and Depression: A Randomized Experimental Therapeutics Trial Targeting Social Reward Sensitivity to Enhance Social Connectedness

BACKGROUND

Social disconnection is common and causes significant impairment in anxiety and depressive disorders, and it does not respond sufficiently to available treatments. The positive valence system supports social bond formation and maintenance but is often hyporesponsive in people with anxiety or depression. We conducted an experimental therapeutics trial to test the hypothesis that targeting positive valence processes through cognitive and behavioral strategies would enhance responsivity to social rewards, a core mechanism underlying social connectedness.

METHODS

Sixty-eight adults who endorsed clinically elevated anxiety and/or depression with social impairment were randomized 1:1:1 to 5 (n = 23) or 10 (n = 22) sessions of amplification of positivity (AMP) treatment or waitlist (n = 23). Pre- to posttreatment change in striatal activity (primary outcome) during social reward anticipation was measured using functional magnetic resonance imaging, and reactivity to a social affiliation task (secondary) and self-reported social connectedness (exploratory) were examined. Primary analyses compared AMP (doses combined) versus waitlist. A second aim was to compare the effects of different doses.

RESULTS

AMP engaged the hypothesized treatment target, leading to greater striatal activation during anticipation of social rewards versus waitlist (d = 1.01 [95% CI = 0.42-1.61]; largest striatal volume). AMP yielded larger improvements in positive affect and approach behavior during the affiliation task (but not other outcomes) and social connectedness. Larger striatal and social connectedness increases were observed for 5-session versus 10-session AMP (d range = 0.08-1.03).

CONCLUSIONS

Teaching people with anxiety or depression strategies to increase positive thoughts, behaviors, and emotions enhances activity in brain regions that govern social reward processing and promotes social connectedness. Social reward sensitivity may be a transdiagnostic target for remediating social disconnection.

Altered Putamen Activation for Social Comparison-Related Feedback in Social Anxiety Disorder: A Pilot Study

INTRODUCTION

Social anxiety disorder (SAD) is characterized by abnormal processing of performance-related social stimuli. Previous studies have shown altered emotional experiences and activations of different sub-regions of the striatum during processing of social stimuli in patients with SAD. However, whether and to what extent social comparisons affect behavioural and neural responses to feedback stimuli in patients with SAD is unknown.

MATERIALS AND METHODS

To address this issue, emotional ratings and functional magnetic resonance imaging (fMRI) responses were assessed while patients suffering from SAD and healthy controls (HC) were required to perform a choice task and received performance feedback (correct, incorrect, non-informative) that varied in relation to the performance of fictitious other participants (a few, half, or most of others had the same outcome).

RESULTS

Across all performance feedback conditions, fMRI analyses revealed reduced activations in bilateral putamen when feedback was assumed to be received by only a few compared to half of the other participants in patients with SAD. Nevertheless, analysis of rating data showed a similar modulation of valence and arousal ratings in patients with SAD and HC depending on social comparison-related feedback.

CONCLUSIONS

This suggests altered neural processing of performance feedback depending on social comparisons in patients with SAD.

Transdiagnostic considerations of the relationship between reward sensitivity and psychopathological symptoms - a cross-lagged panel analysis

BACKGROUND

Reward sensitivity constitutes a potential key mechanism regarding the etiology and maintenance of mental disorders, especially depression. However, due to a lack of longitudinal studies, the temporal dynamics are not clear yet. Although some evidence indicates that reward processing could be a transdiagnostic mechanism of disorders, these observations could be also a product of comorbidity with depression. This study aimed at investigating the temporal dynamics of reward sensitivity and the course of psychopathological symptoms in a longitudinal investigation, while taking a possible mediating role of depression into account.

METHODS

We conducted a three-wave longitudinal online survey with a 4-week interval. A total of N = 453 participants filled out all three questionnaires. Reward sensitivity was assessed with the Positive Valence System Scale-21 (PVSS-21), depression with the Patient Health Questionnaire (PHQ-9), eating disorder symptoms with the Eating Disorder Examination-Questionnaire-8 (EDE-Q-8), social anxiety with the Mini-social phobia inventory (Mini-SPIN) and alcohol consumption with the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C). Cross-lagged panels and mediation analyses were calculated using path analyses.

RESULTS

Depressive and eating disorder symptoms predicted reward insensitivity at later points in time. Effects were larger from T2 to T3. A bidirectional relationship concerning social anxiety was found. Higher alcohol consumption predicted higher reward sensitivity. Depression at T2 fully mediated the association between psychopathological symptoms at T1 and reward sensitivity at T3 for social anxiety and eating disorder symptoms.

CONCLUSIONS

Our findings imply that reduced reward sensitivity seems to be a consequence rather than an antecedent of psychopathological symptoms. Comorbid depression plays a crucial role in other mental disorders regarding observed hyposensitivity towards rewards. Therefore, our results do not support a transdiagnostic notion of reward sensitivity, but they indicate a potential role of reward sensitivity for symptom persistence.

TRIAL REGISTRATION

The study was preregistered at the Open Science Framework (OSF) ( https://archive.org/details/osf-registrations-6n3s8-v1 ; registration DOI https://doi.org/10.17605/OSF.IO/6N3S8 ).

Event-related potentials during the ultimatum game in people with symptoms of depression and/or social anxiety

Depression and social anxiety are common disorders that have a profound impact on social functioning. The need for studying the neural substrates of social interactions in mental disorders using interactive tasks has been emphasized. The field of neuroeconomics, which combines neuroscience techniques and behavioral economics multiplayer tasks such as the Ultimatum Game (UG), can contribute in this direction. We assessed emotions, behavior, and Event-Related Potentials in participants with depression and/or social anxiety symptoms (MD/SA, n = 63, 57 females) and healthy controls (n = 72, 67 females), while they played the UG. In this task, participants received fair, mid-value, and unfair offers from other players. Mixed linear models were implemented to assess trial level changes in neural activity. The MD/SA group reported higher levels of sadness in response to mid-value and unfair offers compared to controls. In controls, the Medial Frontal Negativity associated with fair offers increased over time, while this dynamic was not observed in the MD/SA group. The MD/SA group showed a decreased P3/LPP in all offers, compared to controls. These results indicate an enhanced negative emotional response to unfairness in the MD/SA group. Neural results reveal a blunted response over time to positive social stimuli in the MD/SA group. Moreover, between-group differences in P3/LPP may relate to a reduced saliency of offers and/or to a reduced availability of resources for processing incoming stimuli in the MD/SA group. Findings may shed light into the neural substrates of social difficulties in these disorders.

Examining social reinforcement learning in social anxiety

BACKGROUND AND OBJECTIVES

Reinforcement learning biases have been empirically linked to anhedonia in depression and theoretically linked to social anhedonia in social anxiety disorder, but little work has directly assessed how socially anxious individuals learn from social reward and punishment.

METHODS

N = 157 individuals high and low in social anxiety symptoms completed a social probabilistic selection task that involved selecting between pairs of neutral faces with varying probabilities of changing to a happy or angry face. Computational modeling was performed to estimate learning rates. Accuracy in choosing the more rewarding face was also analyzed.

RESULTS

No significant group differences were found for learning rates. Contrary to hypotheses, participants high in social anxiety showed impaired punishment learning accuracy; they were more accurate at choosing the most rewarding face than they were at avoiding the most punishing face, and their punishment learning accuracy was lower than that of participants low in social anxiety. Secondary analyses found that high (vs. low) social anxiety participants were less accurate at selecting the more rewarding face on more (vs. less) punishing face pairs.

LIMITATIONS

Stimuli were static, White, facial images, which lack important social cues (e.g., movement, sound) and diversity, and participants were largely non-Hispanic, White undergraduates, whose social reinforcement learning may differ from individuals at different developmental stages and those holding more marginalized identities.

CONCLUSIONS

Socially anxious individuals may be less accurate at learning to avoid social punishment, which may maintain negative beliefs through an interpersonal stress generation process.

Self-evaluation of social-rank in socially anxious individuals associates with enhanced striatal reward function

BACKGROUND

Negative self-views, especially in the domain of power (i.e. social-rank), characterize social anxiety (SA). Neuroimaging studies on self-evaluations in SA have mainly focused on subcortical threat processing systems. Yet, self-evaluation may concurrently invoke diverse affective processing, as motivational systems related to desired self-views may also be activated. To investigate the conflictual nature that may accompany self-evaluation of certain social domains in SA, we examined brain activity related to both threat and reward processing.

METHODS

Participants (N = 74) differing in self-reported SA-severity underwent fMRI while completing a self-evaluation task, wherein they judged the self-descriptiveness of high- v. low-intensity traits in the domains of power and affiliation (i.e. social connectedness). Participants also completed two auxiliary fMRI tasks designated to evoke reward- and threat-related activations in the ventral striatum (VS) and amygdala, respectively. We hypothesized that self-evaluations in SA, particularly in the domain of power, involve aberrant brain activity related to both threat and reward processing.

RESULTS

SA-severity was more negatively associated with power than with affiliation self-evaluations. During self-evaluative judgment of high-power (e.g. dominant), SA-severity associated with increased activity in the VS and ventromedial prefrontal cortex. Moreover, SA-severity correlated with higher similarity between brain activity patterns activated by high-power traits and patterns activated by incentive salience (i.e. reward anticipation) in the VS during the reward task.

CONCLUSIONS

Our findings indicate that self-evaluation of high-power in SA involves excessive striatal reward-related activation, and pinpoint the downregulation of VS-VMPFC activity within such self-evaluative context as a potential neural outcome for therapeutic interventions.

Associations between resting-state neural connectivity and positive affect in social anxiety disorder

INTRODUCTION

Social anxiety disorder (SAD) has been characterized by deficits in social motivation and lack of reactivity to pleasurable stimuli (i.e., positive affect; [PA]). Recent neuroimaging work has shifted toward examining positively valenced motivational systems in SAD focused on reward responses. However, little is known about the associations of reward connectivity and PA in individuals with SAD. As such, the purpose of the current study was to determine whether connectivity among key units of reward neurocircuitry meaningfully relate to PA and whether these key units are more heterogeneous in SAD as compared to controls.

METHODS

Thirty-one participants who met diagnostic criteria for SAD and 33 control participants were included (Mage = 24.8, SD = 6.9; 55% cisgender man). Seed-based timeseries correlations were conducted in NiTime to extract region of interest (ROI) coupling correlation strength values. ANOVAs were carried out to assess whether individuals with SAD differed in ROI-to-ROI connectivity strength as compared to controls. Correlations and variance analyses were also conducted to examine the relationship between ROI-to-ROI connectivity strength and PA, as well as heterogeneity in connectivity strength and PA expression.

RESULTS

Weaker connectivity between the left and right orbital frontal cortex was observed when comparing the SAD to the control group. Within the SAD group, PA was associated with several reward-related ROI couplings; however, these links were not observed among controls. Results further demonstrated that individuals with SAD had significantly more variability in reward connectivity strength as compared to controls.

CONCLUSION

Overall, these results provide emergent evidence for the association between reward regions and PA in individuals with SAD. Additionally, these findings show that individuals with SAD demonstrate greater heterogeneity in reward connectivity.

Anticipating social feedback involves basal forebrain and mesolimbic functional connectivity

The mesolimbic system and basal forebrain (BF) are implicated in processing rewards and punishment, but their interplay and functional properties of subregions with respect to future social outcomes remain unclear. Therefore, this study investigated regional responses and interregional functional connectivity of the lateral (l), medial (m), and ventral (v) Substantia Nigra (SN), Nucleus Accumbens (NAcc), Nucleus basalis of Meynert (NBM), and Medial Septum/Diagonal Band (MS/DB) during reward and punishment anticipation in a social incentive delay task with neutral, positive, and negative feedback using high-resolution fMRI (1.5mm³). Neuroimaging data (n=36 healthy humans) of the anticipation phase was analyzed using mass-univariate, functional connectivity, and multivariate-pattern analysis. As expected, participants responded faster when anticipating positive and negative compared to neutral social feedback. At the neural level, anticipating social information engaged valence-related and valence-unrelated functional connectivity patterns involving the BF and mesolimbic areas. Precisely, valence-related connectivity between the lSN and NBM was associated with anticipating neutral social feedback, while connectivity between the vSN and NBM was associated with anticipating positive social feedback. A more complex pattern was observed for anticipating negative social feedback, including connectivity between the lSN and MS/DB, lSN and NAcc, as well as mSN and NAcc. To conclude, behavioral responses are modulated by the possibility to obtain positive and avoid negative social feedback. The neural processing of feedback anticipation relies on functional connectivity patterns between the BF and mesolimbic areas associated with the emotional valence of the social information. As such, our findings give novel insights into the underlying neural processes of social information processing.

Social anxiety inhibits needs repair following exclusion in both relational and non-relational reward contexts: The mediating role of positive affect

The pain of social exclusion can motivate people to capitalize on opportunities to reconnect with others and repair their self-esteem and feelings of belongingness. This effect is often diminished for those with high social anxiety (HSA). Prior research suggests this may be due to their diminished capacity for recognizing and emotionally responding to relational reward cues. We investigated whether non-relational success experiences in the aftermath of exclusion may be an alternative means of repairing threatened self-esteem and belongingness in HSA individuals. In a preregistered, online study, we threatened belongingness and self-esteem in 422 participants by excluding them in a Cyberball game and then assigned them to one of three conditions: Relational Repair, Non-Relational Repair, or a No-Repair control condition. Results showed that both repair contexts facilitated needs repair relative to the no-repair control condition, and mediation analyses suggested this effect was driven by increased positive affect (PA). HSA individuals were less likely to restore needs regardless of condition and this effect appeared to be driven by low PA. Findings emphasize the critical role of PA for restoring threatened needs in the aftermath of exclusion and suggest that HSA inhibits needs repair processes across both relational and non-relational reward contexts.

Randomized controlled trial of computerized approach/avoidance training in social anxiety disorder: Neural and symptom outcomes

Social anxiety is associated with diminished automatic approach toward positive social cues that may limit the ability to connect with others. This diminished approach bias may be a modifiable treatment target. We evaluated the effects of an approach avoidance training procedure on positive emotions, social relationship outcomes, clinical symptoms, and neural indices of social approach and reward processing. Forty-five individuals with social anxiety disorder were randomized (parallel 1:1 randomization) to complete computerized Approach Positive training (n = 21) or Balanced training(n = 24). Sessions included a standardized social interaction task. Participants were blind to training group. Participants completed clinical outcome measures and functional magnetic resonance imaging at baseline and post intervention with an MRI-compatible AAT and the social incentive delay task (SID). Both groups displayed significant improvements of similar magnitude on the primary outcome of social connectedness (between group post-treatment d = -0.21) but not positive affect (d = -0.09), from before to after treatment, persisting through follow-up. Groups demonstrated significant improvements on additional outcomes including anxiety, depression, and anhedonia symptoms. Participants in Approach Positive AAT demonstrated increased activation in the thalamus and medial prefrontal cortex during social versus neutral- approach relative to Balanced AAT during the fMRI AAT. Participants in Balanced AAT showed increased activation in regions within an a priori-defined striatum region of interest mask during anticipation of social reward (vs. baseline) in the SID relative to Approach Positive AAT. At a neural processing level AAT may influence the valuation and motivations associated with positive social cues regulated by the mPFC and thalamus. NCT02136212, NIMH R00MH090243.

Systematic literature review of human studies assessing the efficacy of cannabidiol for social anxiety

The current review evaluates the potential of cannabidiol (CBD) as a promising pharmacotherapy for social anxiety disorder (SAD). Although a number of evidence-based treatments for SAD are available, less than a third of affected individuals experience symptom remission after one year of treatment. Therefore, improved treatment options are urgently needed, and CBD is one candidate medication that may have certain benefits over current pharmacotherapies, including the absence of sedating side effects, reduced abuse liability, and rapid course of action. The current review provides a brief overview of CBD's mechanisms of action, neuroimaging in SAD, and evidence for CBD's effects on the neural substrates of SAD, as well as systematically reviewing literature directly examining the efficacy of CBD for improving social anxiety among healthy volunteers and individuals with SAD. In both populations, acute CBD administration significantly decreased anxiety without co-occurring sedation. A single study has also shown chronic administration to decrease social anxiety symptoms in individuals with SAD. Collectively, the current literature suggests CBD may be a promising treatment for SAD. However, further research is needed to establish optimal dosing, assess the timecourse of CBD's anxiolytic effects, evaluate long-term CBD administration, and explore sex differences in CBD for social anxiety.

Anhedonia in Anxiety Disorders

Humans, like other animals, are fundamentally motivated to pursue rewarding outcomes and avoid aversive ones. Anxiety disorders are conceptualized, defined, and treated based on heightened sensitivity to perceived aversive outcomes, including imminent threats as well as those that are uncertain yet could occur in the future. Avoidance is the central strategy used to mitigate anticipated aversive outcomes - often at the cost of sacrificing potential rewards and hindering people from obtaining desired outcomes. It is for these reasons that people are often motivated to seek treatment. In this chapter, we consider whether and how anhedonia - the loss of interest in pursuing and/or reduced responsiveness to rewarding outcomes - may serve as a barrier to recovering from clinically impairing anxiety. Increasingly recognized as a prominent symptom in many individuals with elevated anxiety, anhedonia is not explicitly considered within prevailing theoretical models or treatment approaches of anxiety. Our goal, therefore, is to review what is known about anhedonia within the anxiety disorders and then integrate this knowledge into a functional perspective to consider how anhedonia could maintain anxiety and limit treatment response. Our overarching thesis is that anhedonia disrupts the key processes that are central to supporting anxiety recovery. We end this chapter by considering how explicitly targeting anhedonia in treatment can optimize outcomes for anxiety disorders.

From childhood maltreatment to adult inflammation: Evidence for the mediational status of social anxiety and low positive affect

Prior work has established a robust association between childhood maltreatment and systemic inflammatory activation later in life; however, the mechanisms involved in this process remain incompletely understood. The purpose of this investigation was to examine potential mechanistic roles for social anxiety (SA) symptoms and low positive affect (PA) in the path from childhood maltreatment to elevations in circulating interleukin (IL)-6, a common biomarker of inflammatory activation. In addition, building on prior work establishing linkages between mindful awareness and reductions in systemic inflammation, we examined the potential role of trait mindfulness as a moderator of the relationships among childhood maltreatment, SA, low PA, and IL-6. A serial mediation model utilizing a large epidemiologic dataset (final N ​= ​527) supported our central hypothesis that the direct effect of childhood maltreatment on IL-6 was fully serially statistically mediated by SA symptoms and low PA (but not high negative affect). Additionally, results indicated that individuals falling in the upper versus lower quartiles of SA symptoms demonstrated significantly elevated concentrations of IL-6, a finding that has not been previously reported. Trait mindfulness moderated the association between low PA and IL-6, to the exclusion of any paths related to negative affect. Additionally, results indicated that the effect of child maltreatment on IL-6 bypasses SA to indirectly impact IL-6 via negative affect. Overall, we conclude that childhood maltreatment and SA symptoms have a significant influence on IL-6, albeit indirectly via low PA, and the influence of PA on IL-6 may be uniquely susceptible to influence by individual differences in mindfulness.

Expression and co-expression of serotonin and dopamine transporters in social anxiety disorder: a multitracer positron emission tomography study

Serotonin and dopamine are putatively involved in the etiology and treatment of anxiety disorders, but positron emission tomography (PET) studies probing the two neurotransmitters in the same individuals are lacking. The aim of this multitracer PET study was to evaluate the regional expression and co-expression of the transporter proteins for serotonin (SERT) and dopamine (DAT) in patients with social anxiety disorder (SAD). Voxel-wise binding potentials (BP_ND) for SERT and DAT were determined in 27 patients with SAD and 43 age- and sex-matched healthy controls, using the radioligands [¹¹C]DASB (3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile) and [¹¹C]PE2I (N-(3-iodopro-2E-enyl)-2beta-carbomethoxy-3beta-(4'-methylphenyl)nortropane). Results showed that, within transmitter systems, SAD patients exhibited higher SERT binding in the nucleus accumbens while DAT availability in the amygdala, hippocampus, and putamen correlated positively with symptom severity. At a more lenient statistical threshold, SERT and DAT BP_ND were also higher in other striatal and limbic regions in patients, and correlated with symptom severity, whereas no brain region showed higher binding in healthy controls. Moreover, SERT/DAT co-expression was significantly higher in SAD patients in the amygdala, nucleus accumbens, caudate, putamen, and posterior ventral thalamus, while lower co-expression was noted in the dorsomedial thalamus. Follow-up logistic regression analysis confirmed that SAD diagnosis was significantly predicted by the statistical interaction between SERT and DAT availability, in the amygdala, putamen, and dorsomedial thalamus. Thus, SAD was associated with mainly increased expression and co-expression of the transporters for serotonin and dopamine in fear and reward-related brain regions. Resultant monoamine dysregulation may underlie SAD symptomatology and constitute a target for treatment.

Cognitive Neural Mechanism of Social Anxiety Disorder: A Meta-Analysis Based on fMRI Studies

Objective: The present meta-analysis aimed to explore the cognitive and neural mechanism of social anxiety disorder (SAD) from a whole-brain view, and compare the differences in brain activations under different task paradigms. Methods: We searched Web of Science Core Collection and other databases with the keywords related to social anxiety, social phobia, and functional magnetic resonance imaging (fMRI) for comparing persons with SAD to healthy controls and used the activation likelihood estimation method. Thirty-seven papers met the inclusion criteria, including 15 with emotional faces as stimuli, 8 presenting specific situations as stimuli, and 14 using other types of tasks as stimuli. Among these papers, 654 participants were in the SAD group and 594 participants were in the control group with 335 activation increase points and 115 activation decrease points. Results: Whole-brain analysis showed that compared with healthy controls, persons with SAD showed significantly lower activation of the left anterior cingulate gyrus (MNI coordinate: x = −6, y = 22, z = 38; p 0.001). Sub-group analysis based on task indicated that when performing tasks with emotional faces as stimuli, persons with SAD showed significantly lower activation of the left cerebellar slope and fusiform gyrus (MNI coordinate: x = −26, y = −68, z = −12; p 0.001), and significantly higher activation of the right supramarginal gyrus and angular gyrus, than healthy controls (MNI coordinate: x = 58, y = −52, z = 30; p 0.001). Conclusion: Individuals with social anxiety disorder show abnormal activation in the cingulate gyrus, which is responsible for the process of attention control, and task type can influence the activation pattern.

Interoceptive active inference and self-representation in social anxiety disorder (SAD): exploring the neurocognitive traits of the SAD self

This article provides an interoceptive active inference (IAI) account of social anxiety disorder (SAD). Through a neurocognitive framework, we argue that the cognitive and behavioural profile of SAD is best conceived of as a form of maladaptive IAI produced by a negatively biased self-model that cannot reconcile inconsistent tendencies to approach and avoid social interaction. Anticipated future social interactions produce interoceptive prediction error (bodily states of arousal). These interoceptive states are transcribed and experienced as states of distress due to the influence of inconsistent and unstable self-models across a hierarchy of interrelated systems involved in emotional, interoceptive and affective processing. We highlight the role of the insula cortex, in concert with the striatum, amygdala and dorsal anterior cingulate in the generation and reduction of interoceptive prediction errors as well as the resolution of social approach-avoidance conflict. The novelty of our account is a shift in explanatory priority from the representation of the social world in SAD to the representation of the SAD self. In particular, we show how a high-level conceptual self-model of social vulnerability and inadequacy fails to minimize prediction errors produced by a basic drive for social affiliation combined with strong avoidant tendencies. The result is a cascade of interoceptive prediction errors whose attempted minimization through action (i.e. active inference) yields the symptom profile of SAD. We conclude this article by proposing testable hypotheses to further investigate the neurocognitive traits of the SAD self with respect to IAI.

Diagnostic and dimensional evaluation of implicit reward learning in social anxiety disorder and major depression

OBJECTIVE

Increasing evidence supports the presence of an anhedonic endophenotype in major depressive disorder (MDD), characterized by impairments in various components of reward processing, particularly incentive motivation, effort-based decision making, and reward learning. In addition to its prominent role in MDD, reward processing dysregulation has been proposed as a transdiagnostic risk and/or maintenance factor for a range of other forms of psychopathology. Individuals with social anxiety disorder (SAD)-a condition that frequently co-occurs with MDD-demonstrate low trait positive affectivity and altered processing of rewards and positively valenced information. However, no studies to date have directly tested reward learning-the ability to modulate behavior in response to rewards-in this population.

MATERIALS AND METHODS

The current study evaluated reward learning in MDD, SAD, and healthy control subjects (N = 90) using a well-validated signal detection task. Given increasing data supporting transdiagnostic features of psychopathology, we also evaluated associations between anhedonia and task performance transdiagnostically in the patient sample.

RESULTS

Contrary to expectations, results indicated no significant group differences in response bias in the full sample, suggesting no diagnostic differences in reward learning. However, dimensional analyses revealed that higher self-reported anhedonia (but not general distress or anxious arousal) was associated with worse reward learning in both the MDD and SAD groups explaining about 11% of the variance.

CONCLUSION

Deficits in implicit reward learning are associated with anhedonia but not necessarily with major depressive disorder as a diagnosis, which supports the use of transdiagnostic approaches to understanding psychopathology.

Atypical social reward anticipation as a transdiagnostic characteristic of psychopathology: A meta-analytic review and critical evaluation of current evidence

Several psychopathologies (e.g. schizophrenia spectrum conditions, autism spectrum disorders) are characterised by atypical interpersonal and social behaviour, and there is increasing evidence to suggest this atypical social behaviour is related to adjusted behavioural and neural anticipation of social rewards. This review brings together social reward anticipation research in psychopathology (k = 42) and examines the extent to which atypical social reward anticipation is a transdiagnostic characteristic. Meta-analyses of anticipatory reaction times revealed that, in comparison to healthy controls, attention-deficit/hyperactivity disorder, autism spectrum disorder, and schizophrenia spectrum conditions are associated with significantly reduced behavioural anticipation of social rewards. The pooled meta-analysis of anticipatory reaction times found that the full clinical sample demonstrated significant social reward hypoanticipation in comparison to the healthy control group with a medium effect size. A narrative synthesis of meta-analytically ineligible behavioural data, self-report data, and neuroimaging studies complemented the results of the meta-analysis, but also indicated that bipolar disorder, eating disorders, and sexual addiction disorders may be associated with social reward hyperanticipation. The evaluation of existing evidence suggests that future research should better account for factors that affect reward anticipation (e.g. gender, psychotropic medication) and highlights the importance of using stimuli other than happy faces as social rewards.

Mapping gene expression in social anxiety reveals the main brain structures involved in this disorder

Social Anxiety Disorder (SAD) is characterized by emotional and attentional biases as well as distorted negative self-beliefs. According this, we proposed to identify the brain structures and hub genes involved in SAD. An analysis in Pubmed and TRANSFAC was conducted and 72 genes were identified. Using Microarray data, from Allen Human Brain Atlas, it was possible to identify three modules of co-expressed genes from our gene set (R package WGCNA). Higher mean gene expression was found in cortico-medial group, basomedial nucleus, ATZ in amygdala and in head and tail of the caudate nucleus, nucleus accumbens and putamen in striatum. Our enrichment analysis identified the followed hub genes: DRD2, HTR1A, JUN, SP1 and HDAC4. We suggest that SAD is explained by delayed extinction of circuitry for conditioned fear. Caused by reduced activation of the dopaminergic and serotonergic systems,due diminished expectation of reward during social interactions.

Reward Circuitry and Motivational Deficits in Social Anxiety Disorder: What Can Be Learned From Mouse Models?

Social anxiety disorder (SAD) is a common and serious psychiatric condition that typically emerges during adolescence and persists into adulthood if left untreated. Prevailing interventions focus on modulating threat and arousal systems but produce only modest rates of remission. This gap in efficacy suggests that most mainstream treatment concepts do not sufficiently target core processes involved in the onset and maintenance of SAD. This idea has further driven the development of new theoretical models that target dopamine (DA)-driven reward circuitry and motivational deficits that appear to be systematically altered in SAD. Most of the available data linking systemic alterations in DA neurobiology to SAD in humans, although abundant, remains at the level of correlational evidence. Accordingly, the purpose of this brief review is to critically evaluate the relevance of experimental work in rodent models that link details of DA function to symptoms of social anxiety. We conclude that, despite certain systematic limitations inherent in animal models, these approaches provide useful insights into human biomarkers of social anxiety including that (1) adolescence may serve as a critical period for the convergence of neurobiological and environmental factors that modify future expectations about social reward through experience dependent changes in DA-ergic circuitry, (2) females may show unique susceptibility to social anxiety symptoms when encountering relational instability that influences DA-related neural processes, and (3) separate from fear and arousal systems, the functional neurobiology of central DA systems contribute uniquely to susceptibility and maintenance of anhedonic factors relevant to human models of SAD.

The predictive value of neural reward processing on exposure therapy outcome: Results from a randomized controlled trial

BACKGROUND

Exposure is the gold standard treatment for phobic anxiety and is thought to represent the clinical application of extinction learning. Reward sensitivity might however also represent a predictive factor for exposure therapy outcome, as this therapy promotes positive experiences and involves positive comments by the therapist. We hypothesized that high reward sensitivity, as expressed by elevated reward expectancy and reward value, can be associated with better outcome to exposure therapy specifically.

METHODS

Forty-four participants with a specific phobia for spiders were included in the current study. Participants were randomly assigned to exposure therapy (n = 25) or progressive muscle relaxation (PMR) (n = 19). Treatment outcome was defined as pre- versus post-therapy phobia symptoms. Before treatment, functional brain responses and behavioral responses (i.e. reaction time and accuracy) during reward anticipation and consumption were assessed with the Monetary Incentive Delay task (MID). Behavioral and neural responses in regions of interest (i.e. nucleus accumbens, ventromedial prefrontal cortex and the ventral tegmental area) as well as across the whole-brain were subsequently regressed on treatment outcomes.

RESULTS

Exposure therapy was more effective in reducing phobia symptoms than PMR. Longer reaction times to reward cues and lower activation in the left posterior cingulate cortex during reward consumption were selectively associated with symptoms reductions following exposure therapy but not following PMR. Only within the exposure therapy group, greater symptom reduction was related to increased activation in the ventrolateral prefrontal cortex during reward anticipation, and decreased activation in the medial prefrontal cortex during reward consumption.

CONCLUSION

Results indicate that individual differences in reward sensitivity can specifically predict exposure therapy outcome. Although activation in regions of interest were not related to therapy outcome, regions involved in attentional processing of reward cues were predictive of phobic symptom change following exposure therapy but not PMR.

Impaired generalization of reward but not loss in obsessive-compulsive disorder

BACKGROUND

Generalizing from past experiences can be adaptive by allowing those experiences to guide behavior in new situations. Generalizing too much, however, can be maladaptive. For example, individuals with pathological anxiety are believed to overgeneralize emotional responses from past threats, broadening their scope of fears. Whether individuals with pathological anxiety overgeneralize in other situations remains unclear.

METHODS

The present study (N = 57) used a monetary sensory preconditioning paradigm with rewards and losses to address this question in individuals with obsessive-compulsive disorder (OCD) and social anxiety disorder (SAD), comparing them to healthy comparison subjects (HC). In all groups, we tested direct learning of associations between cues and reward vs. loss outcomes, as well as generalization of learning to novel choice options.

RESULTS

We found no differences between the three groups in the direct learning of stimuli with their outcomes: all subjects demonstrated intact stimulus-response learning by choosing rewarding options and avoiding negative ones. However, OCD subjects were less likely to generalize from rewards than either the SAD or HC groups, and this impairment was not found for losses. Additionally, greater deficits in reward generalization were correlated with severity of threat estimation, as measured by a subscale of the Obsessive Beliefs Questionnaire, both within OCD and across all groups.

CONCLUSIONS

These findings suggest that a compromised ability to generalize from rewarding events may impede adaptive behavior in OCD and in those susceptible to high estimation of threat.

Neuroimaging Predictors and Mechanisms of Treatment Response in Social Anxiety Disorder: an Overview of the Amygdala

PURPOSE OF REVIEW

Aberrant amygdala activity is implicated in the neurobiology of social anxiety disorder (SAD) and is, therefore, a treatment target. However, the extent to which amygdala predicts clinical improvement or is impacted by treatment has not been critically examined. This review highlights recent neuroimaging findings from clinical trials and research that test links between amygdala and mechanisms of action.

RECENT FINDINGS

Neuropredictor studies largely comprised psychotherapy where improvement was foretold by amygdala activity and regions beyond amygdala such as frontal structures (e.g., anterior cingulate cortex, medial prefrontal cortex) and areas involved in visual processes (e.g., occipital regions, superior temporal gyrus). Pre-treatment functional connectivity between amygdala and frontal areas was also shown to predict improvement signifying circuits that support emotion processing and regulation interact with treatment. Pre-to-post studies revealed decreases in amygdala response and altered functional connectivity in amygdala pathways regardless of treatment modality. In analogue studies of fear exposure, greater reduction in anxiety was predicted by less amygdala response to a speech challenge and amygdala activity decreased following exposures. Yet, studies have also failed to detect amygdala effects reporting instead treatment-related changes in regions and functional systems that support sensory, emotion, and regulation processes. An array of regions in the corticolimbic subcircuits and extrastriate cortex appear to be viable sites of action. The amygdala and amygdala pathways predict treatment outcome and are altered following treatment. However, further study is needed to establish the role of the amygdala and other candidate regions and brain circuits as sites of action.

A Pilot Study of the Effects of Mindfulness-Based Cognitive Therapy on Positive Affect and Social Anxiety Symptoms

Randomized controlled trials have demonstrated that mindfulness-based cognitive therapy (MBCT) is efficacious in reducing residual depressive symptoms and preventing future depressive episodes (Kuyken et al., 2016). One potential treatment effect of MBCT may be improvement of positive affect (PA), due to improved awareness of daily positive events (Geschwind et al., 2011). Considering social anxiety disorder (SAD) is characterized by diminished PA (Brown et al., 1998; Kashdan, 2007), we sought to determine whether MBCT would reduce social anxiety symptoms, and whether this reduction would be associated with improvement of PA deficits. Adults (N = 22) who met criteria for varied anxiety disorders participated in a small, open-label trial of an 8-week manualized MBCT intervention. Most participants presented with either a diagnosis (primary, secondary, or tertiary) of generalized anxiety disorder (GAD) (N = 15) and/or SAD (N = 14) prior to treatment, with eight individuals meeting diagnostic criteria for both GAD and SAD. We hypothesized participants would demonstrate improvements in social anxiety symptoms, which would be predicted by improvements in PA, not reductions in negative affect (NA). Results of several hierarchical linear regression analyses (completed in both full and disorder-specific samples) indicated that improvements in PA but not reductions in NA predicted social anxiety improvement. This effect was not observed for symptoms of worry, which were instead predicted by decreased NA for individuals diagnosed with GAD and both decreased NA and increased PA in the entire sample. Results suggest that MBCT may be efficacious in mitigating social anxiety symptoms, and this therapeutic effect may be linked to improvements in PA. However, further work is necessary considering the small, heterogeneous sample, uncontrolled study design, and exploratory nature of the study.

Altered activation of the ventral striatum under performance-related observation in social anxiety disorder

BACKGROUND

Social anxiety disorder (SAD) is characterized by fear of social and performance situations. The consequence of scrutiny by others for the neural processing of performance feedback in SAD is unknown.

METHODS

We used event-related functional magnetic resonance imaging to investigate brain activation to positive, negative, and uninformative performance feedback in patients diagnosed with SAD and age-, gender-, and education-matched healthy control subjects who performed a time estimation task during a social observation condition and a non-social control condition: while either being monitored or unmonitored by a body camera, subjects received performance feedback after performing a time estimation that they could not fully evaluate without external feedback.

RESULTS

We found that brain activation in ventral striatum (VS) and midcingulate cortex was modulated by an interaction of social context and feedback type. SAD patients showed a lack of social-context-dependent variation of feedback processing, while control participants showed an enhancement of brain responses specifically to positive feedback in VS during observation.

CONCLUSIONS

The present findings emphasize the importance of social-context processing in SAD by showing that scrutiny prevents appropriate reward-processing-related signatures in response to positive performances in SAD.

A Transdiagnostic Review of Negative Symptom Phenomenology and Etiology

In the DSM5, negative symptoms are 1 of the 5 core dimensions of psychopathology evaluated for schizophrenia. However, negative symptoms are not pathognomonic-they are also part of the diagnostic criteria for other schizophrenia-spectrum disorders, disorders that sometimes have comorbid psychosis, diagnoses not in the schizophrenia-spectrum, and the general "nonclinical" population. Although etiological models of negative symptoms have been developed for chronic schizophrenia, there has been little attention given to whether these models have transdiagnostic applicability. In the current review, we examine areas of commonality and divergence in the clinical presentation and etiology of negative symptoms across diagnostic categories. It was concluded that negative symptoms are relatively frequent across diagnostic categories, but individual disorders may differ in whether their negative symptoms are persistent/transient or primary/secondary. Evidence for separate dimensions of volitional and expressive symptoms exists, and there may be multiple mechanistic pathways to the same symptom phenomenon among DSM-5 disorders within and outside the schizophrenia-spectrum (ie, equifinality). Evidence for a novel transdiagnostic etiological model is presented based on the Research Domain Criteria (RDoC) constructs, which proposes the existence of 2 such pathways-a hedonic pathway and a cognitive pathway-that can both lead to expressive or volitional symptoms. To facilitate treatment breakthroughs, future transdiagnostic studies on negative symptoms are warranted that explore mechanisms underlying volitional and expressive pathology.